Regex literal syntax (/pattern/) in Ruby - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a regex literal in Ruby?

A regex literal in Ruby is a pattern written between slashes, like /pattern/, used to match text.

beginner

How do you write a regex literal to match the word 'cat' exactly?

You write /cat/. This matches the exact sequence of characters 'cat' anywhere in the text.

intermediate

What does the regex literal /\d+/ match?

It matches one or more digits in a row. \d means any digit, and + means one or more times.

intermediate

How do you include options like case-insensitive matching in a regex literal?

Add a letter after the closing slash. For example, /cat/i matches 'cat', 'Cat', or 'CAT'.

intermediate

How do you write a regex literal to match a string that starts with 'hello'?

Use the caret symbol ^ at the start: /^hello/. This matches 'hello' only at the beginning of the text.

What does the regex literal /ruby/ match?

A The exact sequence 'ruby' anywhere in the text

B Only the word 'Ruby' with capital R

C Any word ending with 'ruby'

D Only the start of a string

The regex literal /ruby/ matches the exact sequence 'ruby' anywhere in the text, case-sensitive.

How do you write a regex literal to match one or more digits?

A /\d+/

B /\w+/

C /\s+/

D /\D+/

\d matches digits, and + means one or more times.

What does the i after a regex literal do? For example, /cat/i

A Matches only at the start of the string

B Makes the regex match whitespace

C Matches only digits

D Makes the match case-insensitive

The i flag makes the regex ignore case differences.

Which regex literal matches a string that starts with 'hello'?

A /hello$/

B /^hello/

C /hello/

D /^hello$/

The caret ^ means the start of the string.

How do you write a regex literal to match a newline character?

A /\s/

B /\t/

C /\n/

D /\r/

\n matches a newline character.

Explain how to write a regex literal in Ruby and how to add options like case-insensitivity.

Think about the slashes and letters after them.

Describe how anchors like ^ and $ work inside regex literals.

Anchors fix where the match happens.